Back to EveryPatent.com
United States Patent |
6,249,205
|
Meadors
,   et al.
|
June 19, 2001
|
Surface mount inductor with flux gap and related fabrication methods
Abstract
An inductor, such as for electromagnetic interference (EMI) suppression,
comprises a plurality of ferrite layers arranged in stacked relation and
joined together to define a ferrite body, and a first electrical conductor
extending between a first pair of adjacent ferrite layers. The inductor
includes first respective opposing portions of the first pair of adjacent
ferrite layers being sintered together, and second respective opposing
portions of the first pair of adjacent ferrite layers being in spaced
apart relation to define at least one first gap therebetween. Moreover,
the device includes a sintering blocking material associated with the at
least one first gap. The sintering blocking material causes the gap to
form in the ferrite body to selectively block the magnetic path to thereby
retain a higher inductance than would otherwise be possible at relatively
high currents. In a surface mounting embodiment of the inductor, the
ferrite body has a generally rectangular shape. In addition, a pair of end
conductors are provided on opposing ends of the ferrite body to facilitate
surface mounting of the inductor. The sintering blocking material may
comprise a non-magnetic material. In particular, the sintering blocking
material may comprise titanium-dioxide.
Inventors:
|
Meadors; Richard W. (Chattanooga, TN);
Smith; James A. (Soddy Daisy, TN);
Cameron; Craig P. (Lyons, CO);
Le; Phuong (Hixson, TN)
|
Assignee:
|
Steward, Inc. (Chattanooga, TN)
|
Appl. No.:
|
197743 |
Filed:
|
November 20, 1998 |
Current U.S. Class: |
336/200; 336/83; 336/178 |
Intern'l Class: |
H01F 005/00 |
Field of Search: |
336/200,236,233,178,83
|
References Cited
U.S. Patent Documents
4117588 | Oct., 1978 | Johnson | 336/200.
|
4547961 | Oct., 1985 | Bokil et al. | 336/200.
|
4959631 | Sep., 1990 | Hasegawa et al. | 336/200.
|
5250923 | Oct., 1993 | Ushino et al. | 336/200.
|
Foreign Patent Documents |
5-82736 | Apr., 1993 | JP.
| |
Primary Examiner: Donovan; Lincoln
Assistant Examiner: Nguyen; Tuyen T.
Attorney, Agent or Firm: Allen, Dyer Doppelt Milbrath & Gilchrist, P.A.
Claims
That which is claimed is:
1. An inductor comprising:
a plurality of ferrite layers arranged in stacked relation and joined
together to define a ferrite body;
a first electrical conductor defining a loop extending between a first pair
of adjacent ferrite layers;
first respective opposing portions of the first pair of adjacent ferrite
layers outside the loop being sintered together;
second respective opposing portions of the first pair of adjacent ferrite
layers within the loop being in spaced apart relation to define at least
one first air gap therebetween; and
a sintering blocking material associated with the at least one first air
gap.
2. An inductor according to claim 1 wherein said ferrite body has a
generally rectangular shape.
3. An inductor according to claim 2 further comprising a pair of end
conductors on opposing ends of said ferrite body to facilitate surface
mounting of the inductor.
4. An inductor according to claim 1 wherein said sintering blocking
material comprises a nonmagnetic material.
5. An inductor according to claim 1 wherein said sintering blocking
material comprises titanium-dioxide.
6. An inductor according to claim 1 wherein said sintering blocking
material is at least partially diffused into adjacent ferrite layer
portions.
7. An inductor according to claim 1 further comprising:
a second electrical conductor extending between a second pair of adjacent
ferrite layers;
first respective opposing portions of the second pair of adjacent ferrite
layers being sintered together;
second respective opposing portions of the second pair of adjacent ferrite
layers being in spaced apart relation to define at least one second air
gap therebetween; and
a sintering blocking material associated with the at least one second air
gap.
8. An inductor according to claim 7 wherein said first electrical conductor
and said second electrical conductor are outermost electrical conductors.
9. An inductor according to claim 7 wherein at least one ferrite layer has
at least one via extending therethrough; and further comprising an
electrical conductor extending vertically through the at least one via.
10. An inductor according to claim 9 wherein each electrical conductor
between respective adjacent ferrite layers comprises an enlarged width
portion aligned in registration with each electrical conductor extending
vertically.
11. A surface mount inductor comprising:
a plurality of ferrite layers arranged in stacked relation and joined
together to define a generally rectangular ferrite body;
a first electrical conductor defining a loop extending between a first pair
of adjacent ferrite layers;
first respective opposing portions of the first pair of adjacent ferrite
layers outside the loop being sintered together;
second respective opposing portions of the first pair of adjacent ferrite
layers within the loop being in spaced apart relation to define at least
one first gap therebetween;
a sintering blocking material associated with the at least one first gap;
and
a pair of end conductors on opposing ends of the generally rectangular
ferrite body to facilitate surface mounting.
12. A surface mount inductor according to claim 11 wherein said sintering
blocking material comprises a non-magnetic material.
13. A surface mount inductor according to claim 11 wherein said sintering
blocking material comprises titanium-dioxide.
14. A surface mount inductor according to claim 11 wherein said sintering
blocking material is at least partially diffused into adjacent ferrite
layer portions.
15. A surface mount inductor according to claim 11 further comprising:
a second electrical conductor extending between a second pair of adjacent
ferrite layers;
first respective opposing portions of the second pair of adjacent ferrite
layers being sintered together;
second respective opposing portions of the second pair of adjacent ferrite
layers being in spaced apart relation to define at least one second gap
therebetween; and
a sintering blocking material associated with the at least one second gap.
16. A surface mount inductor according to claim 15 wherein said first
electrical conductor and said second electrical conductor are outermost
electrical conductors.
17. A surface mount inductor according to claim 15 wherein at least one
ferrite layer has at least one via extending therethrough; and further
comprising an electrical conductor extending vertically through the at
least one via.
18. A surface mount inductor according to claim 17 wherein each electrical
conductor between respective adjacent ferrite layers comprises an enlarged
width portion aligned in registration with each electrical conductor
extending vertically.
19. An inductor comprising:
a plurality of ferrite layers joined together to define a ferrite body;
at least one electrical conductor defining a loop extending within the
ferrite body;
first respective opposing portions of a first pair of adjacent ferrite
layers outside the loop being sintered together;
second respective opposing portions of the first pair of adjacent ferrite
layers within the loop being in spaced apart relation to define at least
one gap therebetween; and
a sintering blocking material associated with the at least one gap.
20. An inductor according to claim 19 wherein said sintering blocking
material comprises a non-magnetic material.
21. An inductor according to claim 19 wherein said sintering blocking
material comprises titanium-dioxide.
22. An inductor according to claim 19 wherein at least portions of said
sintering blocking material are diffused into adjacent ferrite layer
portions.
23. An inductor comprising:
a plurality of ferrite layers arranged in stacked relation and joined
together to define a ferrite body;
a first outermost electrical conductor defining a first loop extending
between a first pair of adjacent ferrite layers;
first respective opposing portions of the first pair of adjacent ferrite
layers outside the first loop being sintered together;
second respective opposing portions of the first pair of adjacent ferrite
layers within the first loop being in spaced apart relation to define at
least one first gap therebetween;
a sintering blocking material associated with the at least one first gap;
a second outermost electrical conductor defining a second loop extending
between a second pair of adjacent ferrite layers;
first respective opposing portions of the second pair of adjacent ferrite
layers outside the second loop being sintered together;
second respective opposing portions of the second pair of adjacent ferrite
layers within the second loop being in spaced apart relation to define at
least one second gap therebetween; and
a sintering blocking material associated with the at least one second gap.
24. An inductor according to claim 23 wherein said ferrite body has a
generally rectangular shape.
25. An inductor according to claim 23 further comprising a pair of end
conductors on opposing ends of said ferrite body to facilitate surface
mounting of the inductor.
26. An inductor according to claim 23 wherein said sintering blocking
material comprises a non-magnetic material.
27. An inductor according to claim 23 wherein said sintering blocking
material comprises titanium-dioxide.
28. An inductor according to claim 23 wherein said sintering blocking
material is at least partially diffused into adjacent ferrite layer
portions.
29. An inductor according to claim 23 wherein said first electrical
conductor defines at least a portion of a first loop; wherein said at
least one gap is within said first loop; wherein said second electrical
conductor defines at least a portion of a second loop; and wherein said at
least one second gap is within said second loop.
Description
FIELD OF THE INVENTION
This invention relates to the field of electronic devices, and, more
particularly, to the field of ferrite inductors, such as for
electromagnetic interference (EMI) suppression or ripple smoothing in low
power converters.
BACKGROUND OF THE INVENTION
A typical ferrite surface mount multilayer inductor includes a generally
rectangular ferrite body with an electrically conductive path extending
therethrough. The electrically conductive path, in turn, is connected to
respective conductive coating layers on opposite ends of the ferrite body
to facilitate connection to a printed circuit board, for example. Such a
ferrite component may commonly be manufactured by printing a plurality of
interconnected conductive traces on successive stacked ferrite layers.
U.S. Pat. No. 4,543,553 to Mandai et al. entitled "Chip-Type Inductor"
discloses a chip inductor comprising a plurality of laminated magnetic
layers. Linear conductive patterns extend between the respective magnetic
layers, and these linear conductive patterns are connected successively to
define a coil so as to produce an inductance component. The conductive
patterns on opposite surfaces of the magnetic layers are connected to each
other by through-holes or vias wherein the conductors are deformed to
plunge through the holes to establish electrical contact.
Another device is disclosed in U.S. Pat. No. 4,689,594 to Kawabata et al.
entitled "Multi-Layer Chip Coil." In this patent a multi-layer chip coil
comprises a stack of intermediate layers of magnetizable material having a
through-hole defined therein so as to extend completely through the
thickness thereof. First and second patterned electrical conductors are
formed on the opposite surfaces of each of the intermediate layers, and a
hollow tubular conductive layer extends through the through-hole so as to
connect adjacent conductors.
Still another device is disclosed in U.S. Pat. No. 5,302,932 to Person et
al. entitled "Monolithic Multilayer Chip Inductor and Method For Making
Same." This patent discloses a monolithic multilayer chip inductor which
includes a plurality of subassemblies stacked one above another. Each of
the intermediate subassemblies includes a ferrite layer having a coil
conductor with a uniform width printed on its upper surface. The
intermediate ferrite layers include via holes therein for permitting
interconnection of the conductor coils from one layer to the other. In
addition, one end of the top coil conductor is exposed adjacent the edge
of the chip, and one end of the bottom coil conductor is exposed adjacent
another end of the chip so that the conductors can be connected to end
terminals. Unfortunately, great accuracy may be required in assembling the
layers to provide sufficient electrical contact between each vertical
conductor and the relatively narrow lateral conductors.
Pending U.S. patent application Ser. No. 08/445,475) entitled "High Current
Ferrite Electromagnetic Interference Suppressor and Associated Method",
and assigned to the assignee of the present invention, discloses a
significant improvement in a ferrite inductor having high current handling
capability. The laterally extending conductors may be made relatively
thick and include enlarged width portions to connect to vertically
extending electrical conductors. Unfortunately, the device may still
become saturated at high currents, and, thus, be unable to provide a
desired relatively high inductance at these higher operating currents as
needed in certain applications.
SUMMARY OF THE INVENTION
In view of the foregoing background, it is therefore an object of the
present invention to provide an inductor, such as for EMI suppression or
ripple smoothing, particularly of the surface mount type, for carrying a
relatively high current that is readily manufacturable and which provides
a relatively high inductance.
It is another object of the present invention to provide a manufacturing
method for such an inductor.
These and other objects, features and advantages in accordance with the
present invention are provided by an inductor comprising a plurality of
ferrite layers arranged in stacked relation and joined together to define
a ferrite body. A first electrical conductor extends between a first pair
of adjacent ferrite layers. In addition, the inductor includes first
respective opposing portions of the first pair of adjacent ferrite layers
being sintered together, and second respective opposing portions of the
first pair of adjacent ferrite layers being in spaced apart relation to
define at least one first air gap therebetween. Moreover, the device
includes a sintering blocking material associated with the at least one
first air gap. The sintering blocking material selectively causes an air
gap to form during sintering of the ferrite layers to thereby create an
air gap which will block the magnetic flux path. The resulting inductor
can retain a higher inductance than could an ungapped conventional device,
even at relatively high currents.
In a surface mounting embodiment of the inductor the ferrite body has a
generally rectangular shape. In addition, a pair of end conductors are
provided on opposing ends of the ferrite body to facilitate the surface
mounting of the inductor.
The sintering blocking material may comprise a non-magnetic material. In
particular, the sintering blocking material may comprise titanium-dioxide,
for example. The sintering blocking material may be at least partially
diffused into adjacent ferrite layer portions during the sintering
operation.
In some embodiments of the invention, the first electrical conductor
defines at least a portion of a first loop. The first air gap is defined
within the first loop.
Of course, the inductor may include multiple ferrite layers and multiple
conductors to thereby define a longer coil path through the ferrite body.
In particular, the inductor may include a second electrical conductor
extending between a second pair of adjacent ferrite layers, and have first
respective opposing portions of the second pair of adjacent ferrite layers
being sintered together and second respective opposing portions of the
second pair of adjacent ferrite layers being in spaced apart relation to
define at least one second air gap therebetween. The sintering blocking
material is also preferably associated with the at least one second air
gap to form the gap during sintering.
In one particularly advantageous embodiment of the inductor, the first
electrical conductor and the second electrical conductor are outermost
electrical conductors. In this embodiment two gaps are provided at the
upper and lowermost electrical conductors, and preferably within the loops
defined by each.
At least one of the ferrite layers preferably has at least one via
extending therethrough. Accordingly, the inductor preferably further
comprises an electrical conductor extending vertically through the at
least one via. The vertical conductor can connect the adjacent electrical
conductors to define a coil path through the ferrite body. To facilitate
manufacturing tolerances and retain high current handling capability, the
laterally extending electrical conductors preferably include enlarged
width portions aligned in registration with each vertical electrical
conductor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the inductor in accordance with the present
invention installed on a circuit board in a surface mount configuration.
FIG. 2 is an exploded view of the inductor of FIG. 1.
FIG. 3 is an enlarged transverse cross-sectional view of the inductor as
shown in FIG. 1 and illustrating the air gaps formed in the ferrite body.
FIG. 4 is an enlarged top plan view of a ferrite sheet having a pattern of
lateral electrical conductors thereon as used in the inductor of the
invention.
FIG. 5 is an enlarged bottom plan view of a ferrite sheet having a pattern
of sintering blocking material thereon as used in the inductor of the
present invention.
FIG. 6 is an enlarged top plan view of another ferrite sheet having another
pattern of lateral electrical conductors thereon as used in the inductor
of the present invention.
FIG. 7 is an exploded view illustrating the ferrite sheet for manufacturing
a plurality of inductors of the present invention.
FIG. 8 is a flow chart illustrating the method of making inductors in
accordance with the present invention.
FIG. 9 is a graph of inductance versus current for an inductor having air
gaps in accordance with the present invention and a similar inductor
without the air gaps.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described more fully hereinafter with
reference to the accompanying drawings, in which preferred embodiments of
the invention are shown. This invention may, however, be embodied in many
different forms and should not be construed as limited to the embodiments
set forth herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the scope
of the invention to those skilled in the art. Like numbers refer to like
elements throughout.
Referring initially to FIGS. 1 to 3, an inductor 20 in accordance with the
invention is first described. The inductor 20 comprises a plurality of
ferrite layers 32a-32d, 34, 36a and 36b arranged in stacked relation and
joined together to define a ferrite body 22. One bottom ferrite layer 34
is shown in the illustrated embodiment, along with two top ferrite layers
36a, 36b. Accordingly, two thickness of the ferrite layers are provided to
cover the uppermost electrical conductor and the lowermost electrical
conductor. In other embodiments, different numbers of bottom and top
ferrite layers may be provided as will be readily appreciated by those
skilled in the art.
The illustrated inductor 20 also includes four intermediate ferrite layers
32a-32d each of which includes a respective laterally extending electrical
conductor thereon. The lowest or first intermediate ferrite layer 32a
includes an electrical conductor 38 thereon, and wherein the electrical
conductor includes an end termination portion 40, a generally U-shaped
portion 39, and an enlarged width portion 42. Considered in somewhat
different terms, the electrical conductor 38 has at least a partial loop
shape.
The second intermediate layer 32b includes a lateral electrical conductor
thereon indicated by reference numeral 46. The electrical conductor 46
includes two enlarged width portions 48, 50 connected by a generally
U-shaped portion 47. Similarly, the third intermediate ferrite layer 32c
includes a lateral electrical conductor 52 including two enlarged width
portions 53, 54 connected by a generally U-shaped portion 55. The fourth
intermediate ferrite layer 32d also includes a lateral electrical
conductor 56, which, in turn, includes an end termination portion 57 and
an enlarged width portion 58 connected by a generally U-shaped portion 59.
The lowermost electrical conductor 38 is electrically connected to the
second electrical conductor 46 by the illustrated vertically extending
conductor 44a. Along these lines, the second electrical conductor 46 is
electrically connected to the third electrical conductor 52 by the
illustrated vertically extending electrical conductor 44b. Lastly, in the
illustrated embodiment, the third electrical conductor 52 is electrically
connected to the fourth electrical conductor 56 by the vertical conductor
44c. Of course, the vertically extending conductors extend through vias or
openings punched in the respective ferrite layer as will be readily
appreciated by those skilled in the art. The vertical conductors 44a-44c
may be formed by applying a conductive paste within the respective vias.
In other embodiments, a group of adjacent vertically extending conductors
may be provided in place of the single illustrated vertical conductor as
disclosed, for example, in U.S. patent application Ser. No. 08/445,475,
filed May 22, 1995, now U.S. Pat. No. 5,821,846, referenced above and the
entire disclosure of which is incorporated herein by reference. In
addition, the vertical conductors may be either tubular or solid.
The combination of the lateral and vertical electrical conductors define a
coil or spiral conductive path through the ferrite body 22. In other
embodiments, only a single electrical conductor or other numbers of
electrical conductors may be provided on a respective number of ferrite
layers. The four lateral electrical conductor embodiment inductor 20
illustrated is advantageous because the coil configuration can be readily
achieved and the terminals of the inductor made available for connection
to an external circuit at opposite ends of the device. More particularly,
end conductors 24, 26 are illustratively provided for facilitating surface
mount attachment as by soldering to the circuit board traces 28 of the
circuit board 30 of FIG. 1 as will be readily appreciated by those skilled
in the art.
In accordance with the present invention, desirable relatively high
inductance values are obtained by the inductor 20 despite carrying
relatively high currents. This advantageous property is achieved through
the creation of air gaps 62, 63 in the magnetic flux path through the
generally rectangular ferrite body 22 as shown in the cross-sectional view
of FIG. 3. These air gaps 62, 63 are achieved by providing a sintering
blocking material in selected portions of the stacked ferrite layers.
More particularly, as shown in the exploded view of FIG. 2, a layer of
sintering blocking material 71 is deposited on the underside of the
ferrite layer 32b. This sintering blocking material will thus be
positioned within the boundaries of the partial ring or loop defined by
the first lateral electrical conductor 38. Similarly, a layer of sintering
blocking material 71 is provided on the underside of the upper ferrite
layer 36a in the illustrated embodiment. A small spacing of about 0.010
inches may be left between the edge of the sintering blocking material and
the adjacent portion of the electrical conductor. The layers or patches of
sintering blocking material 70, 71 may be screen printed in position on
the respective undersides of ferrite layers 32b, 36a. Alternately, the
sintering blocking material may be deposited or otherwise positioned on
the ferrite layers within the loops defined by the respective electrical
conductors as will be readily appreciated by those skilled in the art.
The sintering blocking material may preferably comprise titanium dioxide
which is a non-magnetic material and which will prevent the adjacent
ferrite layer portions from sintering together during the sintering step
in the device fabrication. Other materials such as aluminum oxide may also
be used which have similar properties. The sintering blocking material may
remain in the gap between the adjacent opposing ferrite layer portions, or
some, or all of the material may be diffused into the ferrite material as
the ferrite material is somewhat porous as will be readily appreciated by
those skilled in the art.
Considered in other terms, the inductor 20 includes first respective
opposing portions of at least one first pair of adjacent ferrite layers
being sintered together, and second respective opposing portions of the
pair of adjacent ferrite layers being in spaced apart relation to define
at least one air gap therebetween. These first and second portions are
readily seen along the boundary between the ferrite layer 32a and the
adjacent ferrite layer 32b as shown in FIG. 3. The outer edge portions
surrounding the electrical conductor 38 are sintered together as there is
no material at the boundary or interface to prevent such sintering.
However, the interface within the partial loop defined by the electrical
conductor 38 is effected by the sintering blocking material 70 (FIG. 2)
and causes the lower air gap 62 to be formed. This same technique is used
to form the upper air gap 63 as also shown in the cross-section of FIG. 3.
Of course other similar devices could include only a single air gap or
more than two air gaps as will be readily understood by those skilled in
the art.
In the illustrated embodiment of the inductor 20 the air gaps 63, 62 are
used to break the magnetic flux path and retain a relatively high
inductance even at relatively high operating currents as will be described
in an example below. It should also be noted that in some embodiments, the
air gap is formed, but in other embodiments, the non-magnetic material of
the sintering blocking material may remain to partially fill or completely
fill the gap to thereby block the flux path between opposing ferrite layer
portions. Typically the sintering blocking material will prevent the
joining together of the opposing ferrite portions, and air will be
retained in the gap due to the porosity of the ferrite material as will be
readily understood by those skilled in the art. Accordingly, the sintering
blocking material need not be limited to the examples provided herein,
rather, the material need only be non-magnetic and preferably not be so
volatile at the sintering temperatures as to be ineffective for blocking
the sintering of the opposing ferrite portions.
Turning now additionally to FIGS. 5-7 and the flow chart of FIG. 8, the
method of making the inductor in accordance with the present invention is
now described in greater detail. In this portion of the description, prime
notation is used to indicate ferrite sheets that will be used to
simultaneously produce a relatively large number of inductors 20. These
prime designations will correspond with the ferrite layers of FIG. 2 for
clarity.
From the start (Block 100) registration holes and vias are punched in the
ferrite sheets to be assembled. At Block 103 the vias are filled with a
conductive paste. Next at Block 104 the lateral electrical conductors are
printed on the respective ferrite sheets. For example, FIG. 4 shows a top
plan view of a portion of a ferrite sheet 32a' on which a plurality of
lateral electrical conductors 38 are screen printed. Similarly, FIG. 6 is
a top plan view illustrating the lateral electrical conductors 36 on a
ferrite sheet 32b'. The other ferrite sheets 32c', 32d' are similarly
prepared and require no further discussion. Those of skill in the art will
readily appreciate that conventional conductor printing techniques may be
used to form the conductors, and will appreciate that multiple printing
steps may be used if thicker conductive patterns are desired.
The sintering blocking material is screen printed on the underside of the
desired ferrite layers at Block 106. An example of the pattern of the
sintering blocking material on the underside of the ferrite layer 32b' is
shown in FIG. 5. Those of skill in the art will appreciate that a similar
pattern of sintering blocking material may be formed on the underside of
one of the top ferrite sheet 36a'.
The ferrite sheets are laminated together at Block 108. At Block 110, the
partially completed inductors may be diced or cut according to techniques
well known to those skilled in the art. The next step is to sinter the cut
inductors at Block 112 by applying pressure and at a temperature
sufficient to cause the adjacent ferrite portions to sinter or fuse
together to form an almost monolithic body, except for those portions
including the sintering blocking material. The end electrical conductors
24, 26 are then formed on the ends of the inductors (Block 114) by
conventional printing and plating techniques as will also be understood by
those skilled in the art. At Block 115, the end conductors are plated. The
finished inductors 20 may then be tested at Block 116 before the
manufacturing process ends at Block 118.
The inductor 20 according to the present invention including the upper and
lower air gaps 63, 62 provides a higher inductance at higher operating
currents. The increased performance is shown graphically in FIG. 9. More
particularly, the dashed plot 120 represents the performance of an
inductor as described herein, but without the air gaps to break the
magnetic flux. In contrast, the plot 121 represents the performance of an
inductor in accordance with the present invention. At the relatively high
currents of 2 amps and particularly at 5 amps, the inductor 20 in
accordance with the invention provides a greater inductance. The
approximate dimensions of the inductor 20 tested were 0.220"
(width).times.0.200" (length).times.0.136" (height). Accordingly, the high
current performance and inductance is produced in a relatively small
device suitable for surface mounting, for example, and which can be
readily manufactured in accordance with the method aspects of the
invention as will be appreciated by those skilled in the art.
The inductor 20 may be used in many applications, and is particularly well
suited for EMI suppression and in low power converters. Of course, the
technique of sintering blocking for a laminated ferrite inductor can be
extended to many other components and applications as well. Thus, many
modifications and other embodiments of the invention will come to the mind
of one skilled in the art having the benefit of the teachings presented in
the foregoing descriptions and the associated drawings. Therefore, it is
to be understood that the invention is not to be limited to the specific
embodiments disclosed, and that modifications and embodiments are intended
to be included within the scope of the appended claims.
Top